<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>相对定位</title>
    <style>
        .fu {background-color: #ff0;}
        .fu > div {
            width: 100px;
            height: 100px;
        }
        .z1 {
            background-color: #f00;
        }
        .z2 {
            background-color: #0f0;
            position: relative;/*使用相对定位*/
            /*移动参照物:自己原来的位置*/
            top: 50px;
            right: 50px;
            z-index: -1;/*调整层级,数字越大,层级越靠上*/
        }
        .z3 {
            background-color: #00f;
            position: relative;
            z-index:1;
        }
    </style>
</head>
<body>
<div class="fu">
    <div class="z1"></div>
    <div class="z2"></div>
    <div class="z3"></div>
</div>
</body>
</html>